Search Results (150)

Steep olive orchards in northwest Syria are experiencing severe land degradation as a result of unsustainable uphill–downhill tillage, which accelerates erosion and reduces productivity. To address this problem, three tillage systems, no-till natural vegetation strips (NVSs), contour tillage, and uphill–downhill tillage, were evaluated at two research sites, Yakhour and Tel-Hadya, NW Syria. The adoption of no-till NVSs significantly increased soil organic matter (SOM) at both sites, outperforming uphill–downhill tillage. While contour tillage resulted in lower SOM levels than NVSs, it still performed better than the conventional uphill–downhill practice. Contour soil flux (CSF) was lower in Yakhour, where mule-drawn tillage on steep slopes (31–35%) was practiced, compared to higher CSF values in Tel-Hadya, where tractor tillage was applied on gentler slopes (11–13%), which highlights the influence of slope steepness on soil fluxes. Over four years, net soil flux (NSF) indicated greater soil loss under tractor tillage, confirming that mule-drawn tillage is less disruptive. Olive trees with no-till NVSs benefited from protected root systems, improved soil structure through SOM accumulation, reduced erosion risk, and improved surface runoff buffering, which resulted in increased water infiltration and soil water retention. This study was carried out using a participatory technology development (PTD) framework, which guided the entire research process, from diagnosing problems to co-designing, field testing, and refining soil conservation practices. In Yakhour, farmers actively identified the challenges of degradation. They collaboratively chose no-till natural vegetation strips (NVSs) and contour tillage as key interventions, valuing NVSs for their ability to conserve moisture, suppress weeds and pests, and increase olive productivity. The farmer–scientist co-learning network positioned PTD not only as an outreach tool but also as a core research method, enabling locally relevant and scalable strategies to restore soil functions and combat land degradation in northwest Syria’s hilly olive orchards. Full article

Anthropogenic disturbances and morphological constraints pose significant threats to lake–wetland functions. However, conventional assessments often overlook the influence of wetland morphology on the spatial realization of ecosystem services, which limits effective ecological restoration. This study presents a multidimensional framework coupled with the InVEST model to evaluate the Integrated Ecosystem Service Capacity (IESC) in the Jianghan Lake Cluster. The assessment focuses on key ecosystem services, such as habitat quality, carbon storage, and water purification. The results reveal significant morphology-driven heterogeneity in IESC. Zonal optimization strategies, including ecological water replenishment, buffer-strip construction, and polder-to-lake conversion, significantly enhance IESC across conservation, regulation, and restoration zones. Model simulations indicate that these targeted interventions can reduce non-point source pollution by approximately 35%, and increase carbon sequestration and biodiversity indices by 15–20% and 30%, respectively. This study elucidates the coupling mechanisms between lake morphology and ecosystem service capacity and provides a spatial framework for restoring “lake–river–polder” composite wetland systems. Full article

The four serotypes of dengue virus (DENV), types 1 to 4 (DENV-1 to DENV-4), exhibit approximately 60% identity in the encoded amino acid residues of viral proteins. Reverse transcription of RNA extracted from patient serum specimens followed by PCR amplification with serotype-specific probes is the current standard technique for DENV serotyping. However, this method is time- and cost-consuming, and rapid detection systems with low cost are desirable. Previously, we developed a prototype serotype-specific immunochromatography system. That system was composed of four strips with four corresponding distinct sample buffers, each specifically detecting a single DENV serotype. In the present study, we improved this system by combining pairs of strips into one lateral-flow cassette each, providing DENV-1 and DENV-2 detection in one device and DENV-3 and DENV-4 detection in a second device; this strategy successfully reduced the required sample volume. Furthermore, we were able to adjust the composition of the sample buffers such that a single sample buffer sufficed for all four DENV serotype detection reactions, allowing much easier handling of the devices. Evaluation of this new device against laboratory and clinical DENV isolates and clinical specimens from DENV-infected individuals showed sensitivity that was comparable to that of our previous version, yielding serotype specificity of 100%. These new devices are expected to be of use in the clinical setting, accelerating both prospective and retrospective epidemiological studies. Full article

A novel fluorescent probe (PYB) for selective and sensitive detection of Cu²⁺ ions was rationally designed and synthesized via a multi-step organic reaction using pyrene as the fluorophore and salicylaldehyde-diethylenetriamine Schiff base as the recognition moiety. The structural characterization of PYB was confirmed by ¹H NMR, ¹³C NMR, and high-resolution mass spectrometry (HRMS). Photophysical properties investigation revealed that the probe exhibited strong fluorescence emission at 362 nm in DMF/HEPES-NaOH buffer solution (v:v = 1:1, pH 7.4), which underwent a significant fluorescence quenching response (quenching efficiency up to 77%) upon the addition of Cu²⁺, attributed to the formation of a 1:1 PYB-Cu²⁺ complex (binding constant K = 799.65 M⁻¹). The probe showed excellent selectivity for Cu²⁺ over other common metal ions (Ba²⁺, Na⁺, Mg²⁺, Zn²⁺, Cd²⁺, Ca²⁺, Mn²⁺, Pb²⁺, Hg²⁺, Fe³⁺, Co²⁺), with a low detection limit of 8.35 × 10⁻⁷ M, which is well below the maximum allowable concentration of Cu²⁺ in drinking water specified by the World Health Organization (WHO). Furthermore, a portable fluorescent test strip based on PYB was successfully fabricated, enabling rapid and visual detection of Cu²⁺ under UV light. Fluorescence imaging experiments in living HepG2 cells demonstrated that PYB could penetrate cell membranes efficiently and realize the intracellular detection of exogenous Cu²⁺. These results collectively indicate that PYB holds great potential as a practical tool for Cu²⁺ detection in environmental monitoring, food safety, and biological systems. Full article

The article describes innovative procedures for determining In(III) using anodic stripping voltammetry (ASV) and adsorptive stripping voltammetry (AdSV) with cupferron as a chelating agent. In both procedures, an environmentally friendly solid bismuth microelectrode (SBiµE) with a diameter of 25 µm was used as the working electrode. In both procedures, 0.1 mol L⁻¹ acetate buffer with a pH of 3.0 ± 0.05 was used as the supporting electrolyte. The electrochemical measurement conditions were as follows: −2.4 V for a 20 s activation step and −1.2 V for a 20 s accumulation step for ASV, and −2.5 V for a 45 s activation step and −0.65 V for a 10 s accumulation step for AdSV. The signal was recorded as a result of a positive potential change from −1.0 to −0.3 V in the case of the ASV procedure and as a result of a negative potential change from −0.4 to −1.0 V in the case of the AdSV procedure. The calibration graph was linear from 5 × 10⁻⁹ mol L⁻¹ to 5 × 10⁻⁷ mol L⁻¹ with a detection limit of 1.4 × 10⁻⁹ mol L⁻¹ for ASV and from 1 × 10⁻⁹ mol L⁻¹ to 1 × 10⁻⁷ mol L⁻¹ with a detection limit of 3.9 × 10⁻¹⁰ mol L⁻¹ for AdSV. The effect of interferents such as surfactants, humic substances and EDTA on the analytical signal was compared in the case of signal recording using the ASV technique with the signal recorded using the AdSV technique. Based on the results obtained, it was determined how the charge of interferents affects the signal depending on the technique used. To validate the practical application of the developed procedures, an analysis of In(III) recovery from samples of the Baltic Sea and Synthetic Sea Water was performed. Full article

A versatile voltammetric procedure for quantitative determination of Pb(II) directly in environmental water samples has been proposed. Differential pulse technique in the variant of anodic stripping voltammetry was applied to study Pb(II) at a solid bismuth microelectrode (SBiµE). The proposed procedure was tested using model solutions containing 0.1 mol L⁻¹ acetate buffer (pH = 3.4) and 5 × 10⁻⁹ mol L⁻¹ Pb(II). Under optimized measurement conditions, i.e., activation potential and time −2.5 V and 30 s, respectively, and accumulation potential and time −1.4 V and 30 s, respectively, a linearity range of 1 × 10⁻¹⁰–3 × 10⁻⁸ mol L⁻¹, a detection limit of 3.4 × 10⁻¹¹ mol L⁻¹ and a relative standard deviation of 3.1% were obtained. The applicability of the developed procedure was confirmed by direct analysis of environmental waters, such as water from the Bystrzyca River and water from the Baltic Sea. Full article

The compounding effects of hydrometeorological hazards are being driven by climate change. As urban areas expand, this leads to degradation of the surrounding environment and exposes more people to hazards. Growing losses show that conventional approaches to addressing these issues can compound these problems. Over the last few decades, nature-based solutions (NBSs) have become an increasingly popular alternative. These measures, inspired by natural processes, have shown potential for reducing hazards by complementing traditional approaches and providing co-benefits in the form of eco-system services. With the adoption of NBSs becoming a more mainstream approach, there is a need for tools that support the planning and implementation of interventions. Geospatial suitability assessment is a part of this planning process. Existing tools are limited in their application for large-scale measures. This paper intends to improve this by building upon a multi-criteria analysis (MCA)-based approach that incorporates biophysical and land use criteria and conditions for mapping the suitability of large-scale NBSs. The methodology was developed and tested on six sites to assess the suitability of floodplain restoration, retention or detention, afforestation, and forest buffer strips. The resulting suitability maps also show potential for combining two or more measures for greater risk reduction. Full article

Seasonal dynamics of dissolved organic matter (DOM) in agricultural ditches significantly impact carbon cycling and water quality in connected rivers. This study aimed to characterize seasonal variations in DOM composition and dynamics within hierarchical agricultural ditch systems in Tianjin, northern China. Surface water samples were collected from river channels, main ditches, branch ditches, lateral ditches, and field ditches during wet (June 2021) and dry (December 2021) seasons. DOM characteristics were analyzed using dissolved organic carbon (DOC) quantification, ultraviolet-visible (UV-Vis) absorption spectroscopy, and three-dimensional excitation–emission matrix spectroscopy (3D-EEMs) coupled with parallel factor analysis (PARAFAC). The concentration of DOC in ditch surface water exhibited significant seasonal variations, with significantly higher levels observed during the wet season (Huangzhuang: 6.72 ± 0.7 mg/L; Weixing: 13.15 ± 3.1 mg/L) compared to the dry season (Huangzhuang: 5.93 ± 0.3 mg/L; Weixing: 9.35 ± 2.6 mg/L). Both UV-Vis spectral and EEM-PARAFAC analysis revealed that DOM in ditch systems was predominantly composed of fulvic-like and tryptophan-like components, representing the portion of organic matter in water bodies that is highly biologically active, highly mobile, relatively “fresh”, or “not fully humified”. PARAFAC identified microbial humic-like (C1: wet season 40.36%, dry season 34.42%) and protein-like (C3: wet season 40.3%, dry season 49.87%) components as dominant. DOM sources were influenced by dual inputs from terrestrial and autochthonous origins during the wet season, while primarily deriving from autochthonous sources in the dry season. This study elucidates the advances of spectroscopic techniques in deciphering the composition, sources, and influencing factors of DOM in aquatic systems. The findings support implementing riparian buffer strips and optimized fertilizer management to mitigate seasonal peaks of bioavailable DOM in agricultural ditch systems. Full article

Various nature-based solutions (NbS)—such as constructed wetlands, drainage ditches, and vegetated buffer strips—have recently demonstrated strong potential for mitigating pollutant transport in open channels and river systems. Numerical modeling is a widely adopted and effective approach for assessing the performance of these interventions. This study presents the first development of a two-dimensional (2D) meshless advection–diffusion model based on an Eulerian smoothed particle hydrodynamics (SPH) framework, specifically designed to simulate passive pollutant transport in open channel flows. The proposed model marks a pioneering application of the ESPH technique to environmental pollutant transport problems. It couples the 2D depth-averaged shallow water equations with an advection–diffusion equation to represent both fluid motion and pollutant concentration dynamics. A uniform particle arrangement ensures that each fluid particle interacts symmetrically with eight neighboring particles for flux computation. To represent the pollutant transport process, the dispersion coefficient is defined as the sum of molecular and turbulent diffusion components. The turbulent diffusion coefficient is calculated using a prescribed turbulent Schmidt number and the eddy viscosity obtained from a Smagorinsky-type mixing-length turbulence model. Three analytical case studies, including one-dimensional transcritical open channel flow, 2D isotropic and anisotropic diffusion in still water, and advection–diffusion in a 2D uniform flow, are employed to verify the model’s accuracy and convergence. The model demonstrates first-order convergence, with relative root mean square errors (RRMSEs) of approximately 0.2% for water depth and velocity, and 0.1–0.5% for concentration. Additionally, the model is applied to a laboratory experiment involving 2D pollutant dispersion in a 90° junction channel. The simulated results show good agreement with measured velocity and concentration distributions. These findings indicate that the developed model is a reliable and effective tool for evaluating the performance of NbS in mitigating pollutant transport in open channels and river systems. Full article

The Soil and Water Assessment Tool (SWAT) was utilized to analyze the spatiotemporal distribution patterns of composite non-point source pollution in the Yapu Port Basin, China, and to quantify the pollutant load contributions from various sources. Scenario-based simulations were designed to assess the effectiveness of different mitigation strategies, focusing on both agricultural and urban non-point source pollution control. The watershed was divided into 39 sub-watersheds and 106 hydrologic response units (HRUs). Model calibration and validation were conducted using the observed data on runoff, total phosphorus (TP), and total nitrogen (TN). The results demonstrate good model performance, with coefficients of determination (R²) ≥ 0.85 and Nash–Sutcliffe efficiencies (NSEs) ≥ 0.84, indicating its applicability to the study area. Temporally, pollutant loads exhibited a positive correlation with precipitation, with peak values observed during the annual flood season. Spatially, pollution intensity increased from upstream to downstream, with the western region of the watershed showing higher loss intensity. Pollution was predominantly concentrated in the downstream region. Based on the composite source analysis, a series of management measures were designed targeting both agricultural and urban non-point source pollution. Among individual measures, fertilizer reduction in agricultural fields and the establishment of vegetative buffer strips demonstrated the highest effectiveness. Combined management strategies significantly enhanced pollution control, with average TN and TP load reductions of 22.18% and 22.70%, respectively. The most effective scenario combined fertilizer reduction, improved urban stormwater utilization, vegetative buffer strips, and grassed swales in both farmland and orchards, resulting in TN and TP reductions of 67.2% and 56.2%, respectively. Full article

The development of rapid, sensitive and cost-effective lateral flow assays is crucial for the detection of mycotoxins, ideally at the point-of-care level. This study presents the design and optimization of a competitive lateral flow assay based on gold nanoparticles (AuNPs) for the detection of zearalenone in food samples. Beginning with the synthesis and functionalization of gold nanoparticles, it proceeds to compare the immobilization of antibodies using chemical conjugation and physical adsorption binding strategies, upon optimizing parameters including the pH, antibody concentration and blocking conditions to enhance the stability of the prepared bioconjugates. The bioconjugates are characterized using UV–visible absorption spectroscopy and dynamic light scattering to monitor changes in the spectra and hydrodynamic size of AuNPs upon the addition of antibodies. The assessment of these bioconjugates is based on their ability to bind and manifest a color, developed due to nanoparticle binding with the test zone on the strip with the toxin–protein conjugate. The lateral flow immunochromatographic assay (LFIA) strips are then prepared by dispensing a control line (IgG) and test line (toxin–protein conjugate) on a nitrocellulose membrane using a lateral flow strip dispenser. The sensitivity of the LFIA strips is evaluated after standardizing the conditions by varying the concentration of zearalenone in the spiked samples and optimizing the running buffer solution. The limit of detection and limit of quantification under optimized conditions are determined to be 0.7 ng/mL and 2.37 ng for zearalenone-spiked samples. Furthermore, the mean pixel intensity and RGB values are plotted against the concentration of zearalenone, which can be used in a colorimetric smartphone-based application for the quantification of the amount of mycotoxin in the sample. Full article

Understanding the impact of vegetation on organic matter content in sediments is essential for sustainable reservoir management and water quality protection. This study examined the relationship between land cover, erosion processes, and organic matter accumulation in the sediments of four small water reservoirs in the Republic of Serbia. Organic matter content was quantified and analyzed in relation to basin characteristics, including land-use composition, absolute and mean flow gradients, and sediment grain size distribution. Field sampling was conducted across the catchments of four small water reservoirs—Duboki potok, Resnik, Ljukovo, and Sot—with sediment samples collected from main tributaries and accumulation basins. A multi-method approach was employed, combining remote sensing for vegetation-cover assessment, granulometric analysis, organic matter evaluation via loss-on-ignition at 350 °C, and statistical correlation analysis to assess the influence of land use and hydrological gradients on sediment composition. The results revealed a strong correlation (R = 0.892) between forest cover and sedimentary organic matter content, confirming the significant role of vegetation in stabilizing sediments and promoting organic matter deposition. Reservoirs with higher forest and shrub cover (e.g., Sot and Duboki potok) exhibited greater organic matter accumulation (5.79–5.98%), while the agriculture-dominated Ljukovo catchment (76.85% agricultural land) recorded the lowest organic matter content (3.89%) due to increased sediment displacement and reduced erosion resistance. These findings underscore the critical role of vegetation in regulating sediment dynamics and enhancing organic matter retention in small water reservoirs. To mitigate excessive organic matter deposition and improve water quality, sustainable watershed management strategies—such as vegetation buffer strips, afforestation, and erosion control measures—are recommended. Full article

Due to the characteristics of high salt and high acidity of the electrolyte and the chemical reaction between thiourea (Tu) and metal ions, it is still a problem to quickly and accurately detect Tu concentration in copper electrolyte. An improved spectrophotometric method has been proposed by simplifying the extraction steps of the traditional extraction–spectrophotometry and reducing the dosage of extractant and buffer. The improved method, with a favorable R² of 0.9991, great precision of 1.67% and excellent spiked recovery of 102.19%, was not affected by the presence of gelatin and copper ions. Moreover, based on the spectrophotometry, a colorimetric method for rapid detection of Tu concentration in copper electrolyte was proposed. Using the standard color card produced enabled the expeditious determination of the concentration range of Tu in copper electrolyte. Since the gray value of the standard color card is linearly related to the Tu concentration, it is feasible to determine the Tu concentration by measuring the gray value of the test strip, and its accuracy was verified by spectrophotometry. The colorimetric method has satisfactory results in industrial practice. This study provides a novel approach for the rapid detection of Tu concentration in the copper electrolysis industry. Full article

This paper shows the fabrication of a new environmentally friendly sensor, an activated glassy carbon electrode with an in situ deposited bismuth film (aGCE/BiF), to determine Cd(II) and Pb(II) at the nanotrace level. The electrochemical activation of the GCE surface was achieved in a solution of 0.1 M phosphate-buffered saline (PBS) of pH = 7 by performing five cyclic voltammetric scans in the range of −1.5–2.5 V at ν of 100 mV/s. The newly developed electrode provides several advantages, such as an increased electron active surface (compared to the glassy carbon electrode) and improved electron transfer kinetics. As a result, the new voltammetric procedure (square-wave anodic stripping voltammetry, SWASV) was established and optimized. With the SWASV method, the following calibration curves and low detection limits (LODs) were obtained for Cd(II) and Pb(II), respectively: 5–100 nM, 0.62 nM, 2–200 nM, and 0.18 nM. The newly prepared method was used to determine the amounts of Pb(II) and Cd(II) in the certified reference material, and the results agreed with the certified values. Moreover, the procedure was successfully applied to determine the Cd(II) and Pb(II) in river samples. The official and standard addition methods validated the measurement results. Full article

Ciprofloxacin is metabolized from enrofloxacin for use in poultry to manage respiratory and gastrointestinal diseases, raising concerns due to its widespread tissue distribution and prolonged systemic persistence. This lateral flow immunoassay was designed to detect ciprofloxacin using an alternative IgY antibody binded with gold nanoparticles to detect ciprofloxacin residue in raw pork meat samples. The developed strip test achieved adequate sensitivity and specificity under the optimized conditions for pH, which is 7.8, and 20% of MeOH in 0.01 M phosphate buffer containing 1% Tween-20 was used for the buffer composition. An antibody concentration of 1.25 µg/mL was used to bind with gold nanoparticles as a probe for detection. The concentration of the test line (coating antigen) and control line (anti-IgY secondary antibody) was 0.5 mg/mL and 0.2 mg/mL, respectively. The efficiency of the developed strip test showed sensitivity with a 50% inhibitory concentration (IC₅₀) of ciprofloxacin at 7.36 µg/mL, and the limit of detection was 0.2 µg/mL. The proposed strategy exhibited potential for monitoring ciprofloxacin in raw pork samples. Full article